1. Field of the Invention
The present invention relates to the establishment of communication within a network between a client, who is usually a potential customer, and a predetermined network location which is usually an enterprise that potentially is able to profit from communication with the client. Frequently such communications are unsolicited by the client, and take place as a result of solicitation by a third party with a pecuniary interest in establishing such communications; for example because they are paid by the enterprise to do so. An example of such a communication is the use of a hyperlink on a banner advert in a web site. In particular the present invention is concerned with enabling the third party to be able to verify to the enterprise that it had a role in the establishment of such communications worthy of pecuniary reward.
2. Description of Related Art
One frequent arena in which this issue arises is the use of the internet to view web pages. A user who gains access to a particular page on the worldwide web does so typically by typing the web address, or Uniform Resource Locator (“URL”) of the page in their web browser (a programme that functions to enable a user to download and display documents on a web page). In fact the act of accessing the page actually involves downloading a copy of most of the digital information that constitutes the page of interest to the computer (i.e. the client) from which the page is being viewed. The downloaded elements of the page are then stored for the duration of that web session in temporary memory, known as a cache, and from which they are viewed; typically the cache for this purpose (known hereinafter as the “session cache”) is located in the client. This manner of accessing and viewing web pages has great efficiency gains. For example, actions such as scrolling up and down a page do not involve the transmission of corresponding commands across the network, since the copy of the web page that is being viewed is not located on the site in question, but in the session cache within the client.
A further caching process is also employed to produce efficiency gains when accessing web pages at sites that have previously been visited. If the browser receives an input URL from a user for a web site that has previously been accessed by the client, it is likely that a copy of many of the elements of the page at the URL in question is stored within a cache located at some point in the network between the web server hosting the web page at the URL in question and the client (for clarity's sake, this type of cache is hereinafter known as a “network cache”). In such a situation, to avoid overloading the web server therefore, the browser will initially retrieve a copy of the available elements of the relevant web page from the network cache. Network caching and session caching are thus distinct activities, although they may frequently both take place during the course of accessing a particular web page; the initial copy of the page being retrieved from network cache, and then stored in session cache for the duration of the web session. These modes of operation both act to reduce unnecessary traffic across the network, unnecessary load on the web server, thus providing the client with more rapid access to web pages, and elements of such pages.
However, in both the case of session caching, and network caching, there are likely to be elements of a web page which the code for the page does not permit to be cached. For example in the case of session caching the browser will intermittently check with the web server (usually in response to an action taken by a user in connection with the copy of the page held in session cache, such as for example in the case of a financial web page, clicking a “Check latest share price” icon), whether it has an up-to-date page, i.e. the page is in conformity with what is on the website. In the case of network caching, elements of pages which change over the time interval between occasions on which the page is accessed are updated by retrieving them from web server for the page of interest (i.e. the original source of the page) the when the page is retrieved from network cache. In both instances, there are also likely to be elements of a page for which caching permissions do not exist for commercial reasons. An example of such an element is an advert from a sponsoring enterprise having a hyperlink re-directing a visitor to the sponsor's website when the advert is clicked, known as a “clickthrough”. A common commercial agreement for a clickthrough requires the sponsor to pay the administrator (for example) of the original web page each time traffic to the original web page is redirected to the sponsor's site from the original site, since in such a situation the original web site is deemed to have successfully solicited communication between the client and the sponsor. However, if the copy of the page including the clickthrough is stored in cache and a client activates the clickthrough to re-direct to the sponsor's site, the administrators of the original site, will be unaware, and so will be unable to charge the sponsor money which is rightfully owing to them under the terms of the commercial agreement with the sponsor.
The effect of these restrictive permissions which prevent caching of such elements of a page is to prevent the ultimate optimisation of performance for such pages, and yet many of these restrictions exist simply because caching creates a problem of recognising or verifying the role of, for example, a clickthrough on a host web site in establishing communication between a client and an enterprise in whose favour the clickthrough is acting. This problem is not limited to website clickthroughs which attract sponsorship, since there are also instances of sites which need to observe traffic levels, or observe some other action other than a clickthrough as part of their operation.
Nor is the problem limited to the worldwide web, or internet, and nor does caching have to take place for the problem to manifest itself. For example a client in the form of a mobile phone may be sent a text message advert containing either a telephone number and menu option such as “DIAL NOW?”, or, in the case of a client mobile which supports WAP operation, a hyperlink to a URL on the world wide web. (NB Henceforth within this specification, adverts, or any other message capable of actuation (for example by clicking a hyperlink, or responding YES to a menu option to DIAL?) to establish communication with a network location will be known as a “pointer”; a term of well-defined scope in computer science, which here is being used in a similar but more general sense). In all of the above instances it is desirable for the dispatchor of the pointer to be able to verify reliably that the advert has been used by the client to establish communication with a particular network location. The same set of circumstances apply, mutatis mutandis, in the case of email messages.